Arguably, at least 50 percent of the material for Comedy Central's "The Daily Show" and "The Colbert Report" comes from Fox News; things the on-air talent says, story selection, patterns across the channel's programming, etc.
With another year on top of the competition, being the butt of the joke apparently bothers Fox very little if at all.
From The Wrap:
[Fox News Executive Vice President of Programming Bill] Shine dismisses the regular barbs the “Daily Show” and “Colbert Report” throw at the channel.
“For some reason people think some of the shows on Comedy Central are news shows. They’re not. They’re comedy shows,” Shine said, adding that the writers’ job is to cherry pick and produce entertaining content.
Asked whether the constant attacks harm the company’s ability to do its daily job, Shine said unequivocally, “No.”